Estrella Mtn Park/ Competitive Loop features 10 miles of hiking trails near Phoenix, AZ.
From Phoenix: Get on to I - 10 and head west. Take the first exit to Phoenix International Raceway; I think it is also 118th ave. Head south off exit for few miles , as you cross over the Gila river you can see PIR in front of you. Drive past PIR and take the left at the sign for the Estrella mtn park competive loop. Follow signs to trailhead up ahead. 5 dollar fee via the honor system on weekdays. Try to throw at least a couple of bucks in.
http://www.tripleblaze.com/trail.php?c=3&i=1232